AND without routine investigations indicating an alternative diagnosis.

Possible:

Progressive dementia; and at least two out of the following four clinical features:

Myoclonus

Visual or cerebellar signs

Pyramidal/extrapyramidal signs

Akinetic mutism

AND the absence of a positive result for any of the four tests above that would classify a case as “probable”AND duration of illness less than two yearsAND without routine investigations indicating an alternative diagnosis.